Both electrochemical and chemical reduction (with strong reducing agents) can be used to reduce vanadium. However, you must be very careful with the reaction solution. YOU MUST WORK UNDER INERT ATMOSPHERE, otherwise, vanadium will be oxidized back to vanadium(IV) since both V(II) and V(III) are very easily oxidized. You can use a glove box or a Schlenk line that work under N2 or Ar for your work.

Hi Dear Harsh The V2+ species is highly sensitive to oxygen and reacts with air oxygen in a short time and oxidize to V3+. If you have a vanadium redox flow battery cell, you can fill the positive and negative electrolyte reservoirs with VOSO4 (V4+) and V3+ electrolytes, respectively. After charging your cell, you have V2O5 and V2+ in positive and negative electrolyte reservoirs. The point is that when you oxidize the V3+ (in charging process), you should continuously inject nitrogen gas on the negative reservoir to prevent the oxidation of V2+. You can do the same with a simple electrolysis cell to convert V3+ to V2+.

Vanadium(II) is catalytically decomposed by a metal, that is to say by zinc itself. Especially if high surface area zinc is used. Thats why often zinc amalgalum is applied (see Jones reductor). The mercury increase the alredy high hydrogen overpotential of the zinc. You could have te same effect by adding a tiny ammount of a soluable mercury salt to your solution. If you are not happy with mercury and have no electrochemical cell, you could try to use zinc with low surface area (zinc rod). I hope my comment was helpful.